Semi conductor arrangement



H. VEIITH SEMI CONDUCTOR ARRANGEMENT Filed May 20, 1955 ,lizz/ewz United States Patent SEMI CONDUCTOR ARRANGEMENT Hans Veith, Karlsruhe, Germany, assignor to Siemens & Halske Aktiengesellschaft, Munich and Berlin, Germany, a corporation of Germany Application May 20, 1955, Serial No. 510,005 In Germany October 31, 1949 Public Law 619, August 23, 1954 Patent expires October 31, 1969 5 Claims. (Cl. 317-237) This invention igconcerned with semi conductors with nonlinear operation curve employing semi conductor material of high dielectric constant, preferably greater than 20.

The use of such a semi conductor material furnishes the possibility to raise the directional effect of the semiconductor, as it has been found that the deviation from linearity is proportional to the dielectric constant. For example, by using as a semi-conductor material semiconducting Rutil (TiO or better still, alkali earth titanates or alkali earth zirconates, particularly barium zirconate or barium titanate, having a dielectric constant exceeding 100 up to about 100,000, directional effect increased by about to 10,000 times will be obtained as compared with materials with a dielectric constant of about 10, While other properties remain the same.

The use of a semi-conductor material with a high dielectric constant also offers the possibility to produce semiconductors provided respectively with greater thickness of the blocking layer and pointed electrodes with greater geometric dimensions than used heretofore, without reducing the directional or amplifier effect as compared with prior structures. For, the deviation from linearity is aside from the proportionality relative to the dielectric constant, already mentioned, inversely proportional to the mean cross section of the areas which are, so far as field strength is concerned non-homogeneous and operative for the directional or amplification effect. A higher directional efiect is accordingly not obtained in such a case, by the use of a semi-conductor material with high dielectric constant, but there is the possibility of respectively producing semi-conductors with relatively thick blocking layer (surface rectifiers) or relatively large geometrically advantageous dimensions for the pointed electrode (point contact rectifier), without thereby causing a deterioration of the directional or amplifier effect, because the weakening of the field non-homogeneity by the increase of the corresponding dimensions is compensated again by the high dielectric constant of the material.

There is accordingly the possibility, upon using such semi-conductor material with point contact as well as with surface rectifiers, to affect the current-voltage characteristics during the fabrication in accordance with the intended use, especially, to simplify the production of crystal amplifiers. For, in the latter case, it is possible to provide a spacing of the electrodes contacting the semiconductor, greater than it was customary heretofore.

A blocking layer with increased thickness as compared with that used before, may be produced in a surface rectifier by exposing the semi-conducting material already during the sintering or thereafter only upon one side to a reducing or weakly oxidizing atmosphere.

With point contact rectifiers, the geometric size of the form of the point may be made larger than heretofore and therefore easily reproduceable. The enlargement of the effective elements of the semi-conductor material or structure offers the advantage of facilitating the provision of a third electrode, for example, to operate as a control electrode in crystal triodes. It will in such case not be necessary to keep the small point spacing, for example, on the order of 0.05 mm. as is required in previously known semi-conductor amplifiers. The spacing may be greater because the weakening of the field nonhomogeneity caused by the greater point spacing is compensated for by the higher dielectric constant of the material.

The dielectric constant of materials, for example, barium titanate assumes at certain temperatures a particularly high value, and it therefore appears advisable to heat a semi-conductor made of such material during the operative actuation thereof so as to impart such temperature thereto.

Changes may be made within the scope and spirit of the appended claims.

I claim':

1. A device of the class consisting of rectifiers and amplifiers, comprising a block-shaped semiconductor body made of alkali earth titanate having a dielectric constant exceeding 100, metallic electrodes in engagement with said body for conducting current thereto which traverses such body, thereby efiecting non-homogeneous field distribution therein for producing at constant temperature non-linear relationship between the voltage placed on said body and the current flowing therethrough.

2. A device according to claim 1 wherein said body is made of a material of the class consisting of barium titanate and alkali earth zirconate and barium zirconate.

3. A device according to claim 2 wherein said body is during the operative use thereof maintained at elevated temperature to increase the dielectric constant exhibited thereby.

4. A device according to claim 2. wherein said body is provided with a relatively thick blocking layer, the relative weakening of the field non-homogeneity caused by said blocking layer being compensated for by the high dielectric constant of such body.

5. A device according to claim 2 comprising at least two electrodes in point contact engagement with said body for applying current thereto, the spacing between the contact points of said electrodes exceeding 0.05 millimeter, the relative weakening of the field non-homogeneity caused by said spacing being compensated for by the high dielectric constant of said body.

Brajer Nov. 18, 1952 Howatt Mar. 31, 1953 

1. A DEVICE OF THE CLASS CONSISTING OF RECTIFIERS AND AMPLIFIERS, COMPRISISING A BLOCK-SHAPED SEMICONDUCTOR BODY MADE OF ALKALI EARTH TITANATE HAVING A DIELECTRIC CONSTANT EXCEEDING 100, METALLIC ELECTRODES IN ENGAGEMENT WITH SAID BODY FOR CONDUCTING CURRENT THERETO WHICH TRAVERSES SUCH BODY, THEREBY EFFECTING NON-HOMOGENEOUS FIELD DISTRIBUTION THEREIN FOR PRODUCING AT CONSTANT TEMPERATURE NON-LINEAR RELATIONSHIP BETWEEN THE VOLTAGE PLACED ON SAID BODY AND THE CURRENT FLOWING THERETHROUGH. 